Electro-expansion device



E.v THOMSON. BLEGTRQ EXPANSION DEVIGE.

`(No Model.)

Patented July 31, V1894.

UNITED STATES ,PATENT OFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOMSON- HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

SPECIFICATION forming part of Letters Patent No. 523,695, dated July 31, 1894. Application filed November 25, 1887. l Serial No. 256,154. (No model.)

To a/ZZ whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented acertain new and useful Electro -Expansion Device, of which the following is a specification.

My invention relates to certain novel devices for indicating the strength of .an electric current or operating a valve or otherdevice, and consists in the novel combinations of apparatus and features of construction hereinafter described wherein the heating effects of a current of electricity upon a coniined body of an expansible iiuid, such as mercury, ether, alcohol or similar iluid, are utilized.

The particular features forming my invention will be iirst described in connection with the accompanying drawings and then specified in the claims.

In the accompanying drawings forming a part of this specification, Figure 1, illustrates a form of apparatus in which the movement of expansion is utilized to indicate directly the strength of the heating current. Fig. 2, illustrates an apparatus in which the movement of the liquid or fluid 'under the expansive action of the heating coil closes an electric circuit thereby operating directly as a switch. Fig. 3, illustrates a form of apparatus in which the receptacle is completely filled with the expansive uid which, upon the application of heat, causes one of the yielding sides of the receptacle to bulge outward carrying with it suitable devices to open or close a circuit, open or close a valve, or for other purposes.

In Fig. 1, the confined body of expansible iuid is shown as placed in an ordinary thermometer bulb provided with the usual graduations on its sides.- Aheating coil C, forming part of an electric circuit is shown in this instance as placed around the exterior of the bulb. It will be understood of course that the coil might be placed within the interior of the bulb as illustrated in Fig. 2, the only condition of the invention in this respect being that the coil shall be in heating proximity to the fluid. Upon the passage of the current the heat developed in the coil serves to expand the confined fluid in the bulb causing it to rise into the vert'icaltube. on the tube will indicate the strength of the heating current.

The reading In Fig. 2, I have shown a U shaped tube one of the legs of which is provided with a bulb shaped terminus B, as shown. The tube is partly iilled with a heavy conducting fluid such as mercury and the bulb is completely fluid such as alcohol or oil or even air resting on the surface of the heavier Iiuid. The coil C, is shown as immersed in the alcohol or oil in the bulb B. When the current is passed -iilled with a comparatively light expansive 6o through the coil, the heat developed causes the fluid, caused by the passage .of the current through the coil C, carrying with it a rod S, or other suitable device which may serve either directly or indirectly to register the exwhich is pressed outward by the expansion of 75 tent ofthe movement of said diaphragm and 8o the strength of the heating current, or to open or close an electric switch or to operate a valve, or to eectuate a variety of other similar pu rposes. v

The coil may be placed in any position so 85 that itis in heating proximity to the iiuid or liquid, but in this form of device I prefer to arrange lit around the box, the box with its Vsurrounding coil being then inclosed in a thick layer of material which is a non-conduc- 9o tor of heat. The movement of an expansible liquid in this case is practically irresistible and may be made to give a multiplied movementv by a lever system or maybe utilized in a variety of ways as will be readily apparent.

I do not claim in'this application any de'- vices depending upon the movement of aconned body of liquid due to the evaporation of that liquid by the heating effects of an electric current. Y

What I claim as my invention is- 1. The combination with a closed receptacle IOO containing a body of expansible fluid, of a heating coil or conductor forming the path of an electric current and applied so as to cause heating and expansion of such liquid, and a non-conducting oase or cover inclosin g the receptacle and conductor, substantially as specied.

2. The combination of a closed receptacle entirely filled with expansible fluid and provided With a yielding Wall or side, a heating coil arranged around the exterior of said receptacle, andmeans actuated by said yielding Wall or side to open or close a valve, switch, ordequivalent device, substantially as specitie State of Massachusetts, this 12th day of No- Veinber, A. D. 1887.

ELII-IU THOMSON.

Witnesses:

J. W. GIBBONEY, Oris K. STUART. 

